PhD position at IFP Energies nouvelles (IFPEN) in Earth sciences, geomechanics Graded damage approach for modelling of fractured regions in subsurface

Application are invited for a full-time PhD position to work within the “Digital Earth” project of the PEPR (Programmes et Equipements Prioritaires de Recherche) exploratoire « Sous-sol – Bien Commun », which brings together Universities and Research Centres with the end goal of improving current knowledge of the physics of coupled phenomena in the subsurface. Key target of the project is to develop a unique Digital Earth platform, thereby giving access to a common quantitative knowledge of the subsurface in the form of skills and an associated digital set of coherent data, models, tools, and workflows.

Within this context, carbon capture and sequestration (CCS) is an important part of the strategy aiming at reducing the impact of human activities on climate change. Namely, geomechanical modelling of CO₂ storage sites is an invaluable tool for managing the mechanical risks associated with CCS and in particular, their long-term integrity, which in turn requires accounting for possible rock fracturing.

A novel approach named "Graded damage" that is able to describe initiation and propagation of defects in quasi-brittle materials under mechanical loading has been recently developed. It consists of a gradient-based regularized model in which a local damage law is augmented via convex constraints of non-local type. The main purpose of the PhD thesis is to extend the graded damage framework to deal with damage of porous media under hydromechanical loads, with progressive feedback on both permeability and mechanical properties of the fractured rocks. The developed model and computational methods will be implemented in Code_Aster, a general-purpose finite element code with parallel architecture and HPC capabilities that is developed by Electricité de France (EDF), distributed under GPL licence and currently in use at IFPEN for thermo-hydro-mechanical couplings. The code will be used for CCS screening simulations. 

This interdisciplinary project, at the crossroad of Earth Sciences and Mechanics, is expected to bring major advancements in the field of multi-physics modelling of the subsurface and to significantly contribute to the understanding of the mechanics of fracture in natural media.